1. Field of the Invention
The present invention relates to a method of developing silver halide light-sensitive materials by means of an automatic processor, particularly to a method for forming high-contrast negative images suitable to photomechanical process for printing of graphic arts by means of an automatic processor.
2. Description of the Prior Art
In the field of graphic arts, an image forming system giving high-contrast photographic properties is required to obtain good reproduction of images of continuous gradation or good reproduction of line images by dotted patterns.
Hitherto, a special developer, called a litho-developer, has been used. The litho-developer contains only hydroquinone as the developing agent, and sulfite in the form of an adduct with formaldehyde to prevent infectious development. The concentration of free sulfite ion is kept extremely low. Accordingly as a result, the litho-developer is easily oxidized by air and cannot be stored for more than three days, which is serious disadvantage.
For obtaining high-contrast photographic properties using a stable developer, a method where hydrazine derivatives are used is known and described for example in U.S. Pat. Nos. 4,224,401; 4,168,977; 4,166,742; 4,311,781; 4,272,606; 4,211,857; and 4,243,739. According to this method, photographic properties of high contrast and high sensitivity are obtained and it is permissible to add sulfite at high concentration levels to a developer. With this method the stability of the developer to air oxidation is remarkably enhanced compared with the litho-methods.
However, when these hydrazine derivatives are used, the pH of the developer is set to a value higher than that of a typical litho-developer and, therefore, the pH value tends to vary. Accordingly, there is a problem in that changes in the pH value cause scattering of photographic properties.
U.S. Pat. No. 4,269,929 describes a method where an amino compound is added to an alkaline developer containing a dihydroxybenzene and a 3-pyrazolidone as a developing agent to raise activity of the developer. As a result sensitization and contrasting are effected in a developer of a lower pH value. However, even in this manner, it is difficult to obtain stable photographic properties for long periods of time such as from 1 to 12 months under varying treatment conditions in cases where the area of films to be treated is large or small.
Further, it is proposed to stabilize photographic properties by improving the manner of replenishing a developer in Japanese Patent Applications (unexamined) Nos. 68725/1974, 110329/1976, 23631/1978, 94926/1978, 100232/1978, 103349/1979 and 44438/1983. However, these methods may be used only in the case of a litho-developer and, accordingly, aging deterioration and deterioration by developing are taken into consideration in the manner of replenishment. The is no description relating to a method for replenishment to stably treat silver halide photographic materials containing a hydrazine derivative for long periods of time by means of an automatic processor and to obtain high contrast images.